1. Computers Are Your Future Chapter 4 Computers Are Your Future © 2008 Prentice-Hall, Inc.

2. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 2 Computers Are Your Future Chapter 4 System Software

3. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 3 What You Will Learn... The two major components of operating system software Why a computer isn’t useful without an operating system The five basic functions of an operating system What happens when you turn on a computer The three major types of user interfaces

4. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 4 What You Will Learn... The strengths and weaknesses of the most popular operating systems The seven essential system utilities Data backup procedures Troubleshooting techniques

5. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 5 System Software  System software includes all of the programs needed to keep a computer and its peripheral devices running smoothly  Two major categories of system software are: Operating systems (OS) System utilities

6. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 6 The Operating System (OS): The Computer’s Traffic Cop  The operating system is a set of programs that perform certain basic functions with a specific type of hardware  The functions of the operating system are: Starting the computer Managing programs Managing memory Handling messages from input and output devices Enabling user interaction with the computer

7. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 7 Starting the Computer  Booting – The process of loading or reloading the operating system into the computer’s memory  The booting processes are: Cold boot – Loads the OS when the power is turned on Warm boot – Reloads the OS when the computer is already on

8. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 8 Starting the Computer The computer copies the kernel from the hard drive into the computer’s memory.  The kernel:  Is the central part of the operating system  Starts all applications  Manages devices and memory  Resides in memory at all times  Performs other essential functions

9. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 9 Starting the Computer The step-by-step booting process (click for each step): BIOS is loaded Power-on Self-test is completed Operating System is loaded System configuration is accomplished System Utilities are loaded Users are authenticated

10. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 10 Step 1: The BIOS and Setup Program  ROM (read only memory) – Permanent and unchanging memory  BIOS (basic input/output system) – The part of the system software that includes the instructions that the computer uses to accept input and output  Load – To transfer from a storage device to memory  BIOS is written onto the ROM.  Setup program – A special program containing settings that control the computer’s hardware The program can be accessed while the BIOS information is visible.

11. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 11 Step 2: The Power-On-Self-Test (POST)  POST (power-on-self-test) – A series of tests conducted on the computer’s main memory (random access memory or RAM), input/output devices, disk drives, and the hard disk. BIOS conducts a Power-On-Self-Test (POST) to check the input/output system for operability.  The computer will produce a beeping sound and an error message will appear on the monitor if any problems are encountered.

12. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 12 Step 3: The Operating System (OS) Loads  BIOS searches for the OS.  Settings in the CMOS―complementary metal-oxide semiconductor―determine where to look for the OS.  The operating system’s kernel is loaded into the computer’s memory.  The OS takes control of the computer and begins loading system configuration information.

13. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 13 Step 4: System Configuration  Registry – A database that stores information about peripherals and software  Peripheral – Device connected to a computer  Driver – A utility program that makes peripheral devices function properly  The system is configured from the operating system’s registry.  Drivers are loaded into memory.

14. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 14 Step 5: System Utilities Loads System utilities are loaded into memory.  Volume control  Antivirus software  PC card unplugging utility

15. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 15 Step 6: User Authentication  Authentication or user login occurs. User name Password  The user interface starts, enabling user interaction with computer programs.

16. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 16 Managing Applications  Single-tasking operating systems run one application program at a time.  Multitasking operating systems have the ability to run more than one application program at a time.  Multitasking is accomplished by: A foreground application – The active program or program in use One or more background applications – Inactive program(s) or program(s) not in use

17. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 17 Example of Multitasking Background application Foreground application

18. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 18 Managing Programs Preemptive multitasking – Enables the operating system to regain control if an application stops working

19. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 19 Managing Memory  Computers use memory to make processing more fluid.  The operating system allocates memory areas for each running program; it keeps programs from interfering with each other.  The operating system uses virtual memory as an extension of random access memory (RAM).

20. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 20 Managing Virtual Memory least recently used data or program instructions page swapped out swap file Virtual memory management hard disk page swapped in most recently transferred data or program instructions memory

21. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 21 Handling Input and Output  Input and output devices generate interrupts, or signals, that tell the operating system that something has happened.  The OS provides interrupt handlers or mini-programs that begin when an interrupt occurs.  Interrupt request (IRQ) lines handle the communications between input/output devices and the CPU.  An IRQ conflict causes system instability when two devices try to use the same IRQ line.

22. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 22 Providing the User Interface  The user interface is that part of the operating system with which the user interacts with a computer.  User interface functions: Start application programs Manage disks and files Shut down the computer safely

23. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 23 Graphical User Interface (GUI) Graphical user interface (GUI):  Uses graphics to create a desktop environment  Icons (small pictures) represent computer resources  Programs run within on-screen windows

24. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 24 Menu-driven User Interface Menu-driven:  Text-based menus are used to show all of the options available to the user.

25. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 25 Command-Line Interface Command-line:  The user is required to type keywords or commands in order to enter data or give instructions

26. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 26 WINDOWS XP MAC OS X Exploring Popular Operating Systems WINDOWS NT WINDOWS CE

27. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 27 MS-DOS LINUX UNIX Exploring Popular Operating Systems

28. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 28 Microsoft Windows Click to view each Windows version (1985-2001) Windows 1.0 (1985)Windows 2.0 (1987)Windows 3.x (1990-1992)Windows NT (1993)Windows 95 (1995)Windows 98 (1998)Windows 2000 (2000)Windows ME (2000)Windows XP (2001)

29. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 29 Windows XP  Released in 2001 by Microsoft  XP is short for “experience”  Uses the same underlying code for all versions  Replaces all previous versions of Windows  Three versions: Windows XP Home Edition Windows XP Professional Windows XP Server

30. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 30 Windows NT  Released in 1993 by Microsoft  Designed for client/server systems  Two components: Windows NT Workstation Windows NT Server  Oriented to business needs  Offers security, remote administration, directory services, and a Web server

31. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 31 Windows CE  Released in 1996 by Microsoft  System used in PDAs or palmtops  Runs simplified versions of Windows programs  Data can be transferred to PCs  Includes handwriting and voice recognition

32. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 32 MAC OS  Created in 1984  First OS to use graphical user interface  Easiest operating system for beginners  A new version, Mac OS X, was released in 2000

33. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 33 Linux  Developed in 1991 by UNIX  Open-source code – Available for all to see and use  Competes with Windows and MAC- OS  Powerful and free  Growing acceptance

34. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 34 MS-DOS  Developed for IBM PCs in 1981  Uses command-line interface  Use is diminishing

35. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 35 UNIX  Developed by AT&T in 1970s  Included first preemptive multitasking system  Developed concepts of file management and path names  Facilitates client/server networking  Widely used by corporations

36. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 36 System Utilities: Tools for Housekeeping  System utilities are programs that help the operating system manage the computer system’s resources.  Types of utilities: Backup software Antivirus software Disk scanning Disk defragmentation File management File-searching software File compression

37. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 37 Backup Software  Backup software includes programs that enable the user to copy data from the hard disk to another storage medium  Types of backups: Full backup Incremental backup

38. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 38 Antivirus Software Antivirus software protects the computer from computer viruses.

39. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 39 File Management Utilities  Known as a file manager  Enables the user to perform various tasks on storage devices using files, folders, and directories  Tasks include: Creating folders Saving, deleting, copying, and moving files and folders Examining the contents of files Launching application programs

40. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 40 Search Search programs enable users to find files on storage devices.

41. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 41 File Compression Utility A file compression utility reduces the size of a file.

42. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 42 Disk Scanning Programs  Disk-scanning utilities are programs that detect and fix physical and logical problems on storage devices.  Disk cleanup utilities are programs that remove files that are no longer needed.

43. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 43 Disk Defragmentation Programs A disk defragmentation program moves data on a storage device to improve performance.

44. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 44 System Update Windows Update keeps the operating system up to date.  windowsupdate.microsoft.com

45. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 45 Troubleshooting Computer startup failure:  Use a boot disk (emergency disk) in the floppy drive. Configuration problems after adding new peripherals:  Start the computer in Windows’ safe mode.  Access safe mode by pressing the F8 key during the startup process.

46. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 46 Troubleshooting System slowdown:  Scan for viruses.  Check the CPU fan.  Defragment the hard disk.

47. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 47 Shutting Down Your System  Click Start, then Turn Off Computer. Standby - low power state Shut Down – turns computer off Restart – reboots computer

48. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 48 Chapter 4 Summary Two of the system software components are the operating system and system utilities. The operating system coordinates the functions of a computer’s hardware and provides support for application programs. An operating system manages programs, memory, and input/output devices, and it also provides a means of communicating with the user. The six steps to start a computer are loading the BIOS, power-on self-test, load operating system, configure system, load utilities, authenticate users.

49. Computers Are Your Future Chapter 4 © 2008 Prentice-Hall, Inc.Slide 49 Chapter 4 Summary ( continued ) Two major operating systems for the personal computer are Microsoft Windows and the Mac OS X. The basic types of user interface are command-line, menu-driven, and graphical. System utilities keep the computer running efficiently. Backup procedures keep data safe. Troubleshooting is helpful for discovering errors.